The invention relates to an energy storage module for a device for the voltage supply, particularly of a motor vehicle, including several prismatic storage cells that are arranged behind one another and stacked in at least one row, and to an energy storage arrangement having the energy storage module.
In a device for the voltage supply of a motor vehicle, usually called a battery, generally a plurality of energy storage modules is used for driving the vehicle, for example, electric vehicles or hybrid vehicles. An energy storage module typically includes several stacked prismatic storage cells. The individual storage cells contain electrochemical cells of the battery. The row of stacked storage cells is preferably braced between two end plates. The two end plates are mutually connected by way of tension rods. The bracing direction is therefore perpendicular to the end plates. In addition to being used for the mechanical fixing of the modules with respect to one another, the end plates and tension rods are particularly used for counteracting a deformation by gas pressure changes that occur during the operation in the electrochemical cells arranged in the interior of the modules. One of the energy storage modules or several of the energy storage modules are usually mounted in a carrying structure, for example, further developed as a housing.
Particularly in a motor vehicle, the energy accumulator is subjected to many different types of thermal stress. In the winter, the extreme ambient temperature of the vehicle will have to be taken into account, depending on the usage area. In the summer, the load caused by the exhaust system is added to the high ambient temperature. Here, temperatures of up to over 100° C. can be reached as a result of a high radiation load. Lithium ion cells should be operated in an ideal operating temperature range of between 20° C. and 40° C. For an optimal operating strategy, particularly a very low temperature difference is necessary between the individual cells of the energy storage module.
It is an object of the present invention to provide an energy storage module and an energy storage arrangement which, while the manufacturing and the assembly are cost-effective, can be operated as efficiently as possible.
This object is achieved by an energy storage module for a device for supplying voltage. In particular, the energy storage module in a motor vehicle is used for driving the vehicle. The energy storage module includes several prismatic storage cell which are arranged behind one another and stacked in at least one row. Furthermore, two end plates and at least one tension element are provided. The at least one row of stacked storage cells is braced between two end plates by way of the tension elements. The end plates have supporting surfaces. By way of these supporting surfaces, the energy storage module can be mounted in a carrying structure. The carrying structure is, for example, a housing in a motor vehicle for accommodating several energy storage modules. Within the scope of the invention, it was recognized that an active temperature exchange takes place between the end plates and the carrying structure. This temperature exchange considerably influences the temperature management of the energy storage module. According to exemplary embodiments of the invention, a thermally insulating element is therefore placed on the supporting surface. As much as possible, this thermally insulating element prevents the heat transfer between the respective end plate and the carrying structure.
For fastening the energy storage modules in the carrying structure, the energy storage module may include at least one bolt. This bolt is preferably constructed as a screw. The bolt projects through the supporting surface and can thereby connect the energy storage module with the carrying structure. The thermally insulating element is particularly arranged such that it is also penetrated by the bolt. For this purpose, the thermally insulating element includes a recess, such as a through hole.
Particularly preferably, a thermally insulating element is placed on all supporting surfaces of all end plates of the energy storage module.
In a development that is easy to design, the thermally insulating element is a washer. This washer is placed on the supporting surface and thereby forms a separation between the end plate and the carrying structure.
As an alternative, it is also conceivable to directly connect the thermally insulating element with a further component of the energy storage module. In a preferred embodiment, the energy storage module includes at least one thermally insulating preform between one of the end plates and the storage cell adjoining the end plate. In addition to the thermal insulation between the storage cell and the end plate, this preform is simultaneously used for electric insulation between the storage cell and the end plate. Preferably, it is now provided that the thermally insulating element, which comes to rest on the supporting surface, is arranged on this preform. In a particularly preferred embodiment, this preform is produced in one piece with at least one of the elements, for example, as an injection-molded part. In this case, the element may consist of the same material as the preform. As an alternative, it is conceivable to provide the thermally insulating element as an insert in the injection molding process for the preform. In this case, the element may consist of any highly heat-insulating material. The preform itself preferably consists of a plastic material.
It is further preferably provided that the preform has a plate-shaped construction. This plate shape has two sides. One side rests against the end plate. The other side rests against the adjoining storage cell. In particular, the preform extends over an entire storage cell front surface facing the end plate. As a result, a full-surface thermal and electric insulation is obtained between the storage cell and the end plate.
The thermally insulating element, which comes to be placed on the supporting surface, particularly preferably projects perpendicularly from the plate-shaped preform. A component of the preform, specifically the separation between the end plate and the storage cell, stands parallel to the end plate and perpendicular with respect to the bracing direction of the energy storage module. Correspondingly, the thermally insulating element stands perpendicular with respect to the end plate and parallel to the bracing direction.
The thermally insulating element preferably has a thickness of between 0.5 mm and 5 mm. Ceramics, plastics, paper or cardboard are preferably selected as the material for the thermally insulating element.
The tension elements are advantageously constructed as tension rods. As an alternative, the tensions elements may also be constructed as one or more tightening straps or as combinations, including a number of screws and nuts.
Exemplary embodiments of the invention further include an energy storage arrangement having a carrying structure and at least one energy storage module resting on the carrying structure. The carrying structure is preferably constructed as a housing for receiving several energy storage modules.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.